The present invention relates to a manufacturing method of a natural fiber composite material for injection molding using a reduced nozzle heating jig, and particularly, to a manufacturing method of a natural fiber composite material for injection molding using a reduced nozzle heating jig, which is configured to include: combining natural fibers and synthetic fibers (S1); heat-pressing the combined ply yarn while passing through a reduced nozzle heating jig 100 and melting and pressing the synthetic fibers and fusing the synthetic fibers to the natural fibers (S2); and palletizing the mixed ply yarn (S3).